This paper presents a case study of a sustainable certification of a building renovation. The new LEED® rating system, GBC Historic BuildingTM protocol, proposed by Green Building Council Italy and addressed to Italian historical heritage, was applied to the High School “A. Canova” in Treviso, chosen because it was built before 1945 and it required a restoration work.
The aim of this paper is to present a retrofit design based on strategies according to three objectives: energy saving, preservation of historical architecture, improvement of indoor environmental quality for users.
The application of GBC Historic BuildingTM protocol has been carried out according to the protocol guidebook. The novelty of this paper is that GBC Historic BuildingTM has been used as a design tool, not as assessment tool, in order to develop a design strategy. At first a building survey of the building has been performed to define the state of art in terms of structural instability and deterioration of surfaces and architectural elements in order to propose the most important renovation measures; the dynamic simulation was performed to calculate the building envelope thermal losses and the building energy demand for heating. Different energy efficiency measures have been proposed and an optimal solution has been defined according to simulation data and cost analysis evaluation. Three main goals have been achieved: the reduction of building energy consumptions up to 39%, the conservation of the historical parts of the building and the attainment of good thermal comfort in school classrooms. A Silver LEED level of certification has been gained.